The present invention relates to slide rails for vehicle seats.
More particularly, the invention concerns a vehicle seat slide rail, comprising at least one first fixed steel section of U-shaped cross section, this first fixed steel section having:
a bottom,
two side flanges extending parallel to each other, each from the bottom up to a free end,
and two fold back flanges extending towards each other respectively from the free ends of the two side flanges, defining between them a slot intended to receive at least one support component adapted to be fixed to the vehicle seat, the first fixed steel section additionally comprising fixing means intended to fix said first fixed steel section to the vehicle floor.
Document EP-A-0 842 807 describes an example of such a slide rail.
Known slide rails of this type are entirely satisfactory, but do however have the drawback of forcing the manufacturer of the slide rail to take care over the external finish of the first fixed steel section, so that there is no chance of the user getting dirty or being injured when in contact with it, and so that the slide rail is of good external appearance.
This finish requirement increases the manufacturing cost of the slide rail, by imposing constraints on the manufacturing process of the first fixed steel section.
Moreover, the first fixed steel section is difficult to integrate perfectly into the vehicle floor, bearing in mind its manufacturing process (cutting and bending sheet steel), which allows only limited choice in respect of the shape of said first fixed steel section.
Lastly, the manufacturing processes currently used to make steel slide rail sections allow only relatively short sections to be made easily, which limits the longitudinal adjustment travel of the seat.
A particular object of the present invention is to overcome these drawbacks.
To this end, according to the invention, the first fixed steel section is fitted into a fixed outer section made by extrusion from a material selected from aluminium-based materials and plastic materials, this outer section being fixed to the first steel section and itself having an approximately U-shaped cross section, with a bottom placed against the bottom of the first steel section, two side flanges which surround the flanges of the first steel section, and two fold back flanges which extend the flanges of said fixed outer section by covering the fold back flanges of the first steel section, and said slide rail additionally comprises a second fixed steel section having the same cross section as the first fixed steel section and which is also fitted into the fixed outer section, the first and second fixed steel sections being simply abutted one behind the other in said fixed outer section.
By means of these arrangements, it is possible to make a longer slide rail without being hindered by the limitations of the processes currently used to manufacture steel slide rail sections.
Besides, the first fixed steel section is completely concealed, which allows the manufacturing process of the first fixed steel section to be simplified, since its outer surface no longer needs to be as meticulously prepared as in slide rails of the prior art.
Moreover, bearing in mind the manufacturing process of the fixed outer section, its shape can be selected much more freely than the shape of the first steel section, so that the slide rail can be integrated perfectly into the vehicle floor.
Furthermore, the fixing of the slide rail on the vehicle floor and the sliding mounting of the seat support component is still made by means of the first fixed steel section, which has better mechanical resistance than the fixed outer section: the performance of the slide rail in terms of mechanical resistance is not therefore reduced relative to steel slide rails of the prior art.
Indeed, on the contrary, the fixed outer section contributes to the mechanical resistance of the slide rail by strengthening the first fixed steel section, which if need be allows the thickness of the steel sheet used to make said fixed section to be reduced. As a result savings can be made in the weight and manufacturing costs of the slide rail.
In preferred versions of the invention, use may possibly be made additionally of one and/or other of the following arrangements:
the flanges of the first fixed steel section are held tightly, without play, between the flanges of the fixed outer section;
the flanges of the fixed outer section each comprise at least one longitudinal inner rib which is supported against the corresponding flange of the first fixed steel section;
the fold back flanges of the fixed outer section are supported against the fold back flanges of the first fixed steel section, by applying the bottom of said first fixed steel section against the bottom of the fixed outer section;
each fold back flange of the fixed outer section comprises at least one longitudinal inner rib which is supported against the corresponding fold back flange of the first fixed steel section;
the bottom of the fixed outer section comprises longitudinal inner ribs which are each supported against a side projection of the bottom of the fixed steel section;
the fixing means of the first fixed steel section comprise at least one hole provided in the bottom of said first fixed steel section to receive a screw intended to be fixed to the vehicle floor, the bottom of the fixed outer section also comprising a hole facing the hole provided in the bottom of the first fixed steel section to allow said screw to pass through;
the fixing means of the first fixed steel section comprise at least one screw which passes through the holes provided in the bottom of the first fixed steel section and in the bottom of the fixed outer section, this screw comprising a widened head which is supported against the bottom of the first fixed steel section;
the fold back flanges of the fixed outer section are extended laterally outwards by projecting rims;
a second fixed steel section having the same cross section as the first fixed steel section and which is also fitted in the fixed outer section, the first and second fixed steel sections being simply abutted one behind the other in said fixed outer section; and
a movable section which slides in the first fixed steel section, this movable section being partially covered by the fixed outer section between the two fold back flanges of the first fixed steel section and said movable section comprising a web which extends parallel to the side flanges of the first fixed steel section and which passes through a slot delimited between the two fold back flanges of the outer section.